This mobile app measures your heart rate by looking at you

Research from the MIT Media Lab has led to this mobile app called Cardiio - Touchless Camera Pulse Sensor.

Cardiio uses your phone’s front camera to analyze the amount of light reflected off of your face; it accurately measures your pulse without any extra hardware. Just hold your phone and look straight into the camera to get your reading, then check out the dashboard to see how it changes over time.

You can learn more here.